package com.cyc.pc;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

//线程之间的通信问题，等待唤醒，通知唤醒
//A num+1
//B num-1
public class B {
    public static void main(String[] args) {
        DataB data = new DataB();
        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                try {
                    data.increment();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"A").start();
        new Thread(()->{
            try {
                for (int i = 0; i < 10; i++) {
                    data.decrement();
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        },"B").start();
        new Thread(()->{
            try {
                for (int i = 0; i < 10; i++) {
                    data.decrement();
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        },"C").start();
        new Thread(()->{
            try {
                for (int i = 0; i < 10; i++) {
                    data.decrement();
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        },"D").start();
    }
}

//资源类
//判断->等待->业务->通知
class DataB{
    private int number = 0;
    Lock lock = new ReentrantLock();
    Condition condition =  lock.newCondition();
    //+1
    public void increment() throws InterruptedException {
        lock.lock();
        try {
            while (number!=0){
                //等待
                condition.await();
            }
            number++;
            System.out.println(Thread.currentThread().getName()+"=>"+number);
            //通知其他线程
            condition.signalAll();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            lock.unlock();
        }
    }

    //-1
    public void decrement() throws InterruptedException {
        lock.lock();
        try{
            while (number==0){
                //等待
                condition.await();
            }
            number--;
            System.out.println(Thread.currentThread().getName()+"=>"+number);
            //通知其他线程
            condition.signalAll();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            lock.unlock();
        }
    }
}
